Western Christianity underwent a major schism beginning in the early 16th century. The rediscovery of previously lost Greek and Roman literature combined with the aftermath of plagues, wars and new technologies spelled trouble for the Roman Catholic Church. It had successfully fought earlier rebellions against its primacy, but its luck ran out in 1517 when Martin Luther posted his 95 Theses on the doors of a German cathedral. A new protesting Christian movement was rising fast, and the church would soon have to find a way to counter it.

Beginnings

Protestantism did not begin with Luther, but found its greatest success from his actions. The newly invented printing press was the Internet modem of its day and made Protestant ideas and the Christian Bible available to almost anyone who was literate. Building upon earlier Christian movements, Luther publicly protested the then-current practices and doctrines of the Catholic Church and publicized his own.

Lutheranism

The main complaint of the 95 Theses, the Church's selling of indulgences for the remission of sins, was just the tip of the iceberg. Luther and other Protestant-minded theologians felt that the Pope was not the final authority of church and secular matters. Individual Christians could only receive eternal salvation through God's grace, and not just through good works or an established church. Catholic doctrines concerning the sacraments, eternal judgment, purgatory, saintly intercession and more were either wrong or in need of reform, they believed.

Reformation

Luther's theology attracted other like-minded Christians and eventually led to the establishment of new Christian denominations. Today's Lutheran and Anglican churches share a direct common heritage with the actions of Luther and his contemporaries. The later offshoots of these original Protestant denominations have an indirect heritage with the original "protesting" movements that inspired Luther and company. The "reformed" theology struck home for Christian believers who felt the established church had lost its way, and inspired many to recommit and openly profess their faith.

Response

Nearly 30 years after Luther posted his complaints, the leaders of the Catholic Church met to assess the damage and chart a new course. The Council of Trent took place in multiple sessions from 1545 until 1563 under three succeeding popes in an attempt to fix what was obviously wrong with church practices and vigorously defend what they felt was right. The council thoroughly condemned the majority of Protestant theology in favor of traditional Roman Catholic doctrines and beliefs and reaffirmed the Church as the ultimate scriptural authority.

Changes

The council made an attempt to clean up previous abuses and re-establish a sense of discipline among its clergy at all levels. While not perfect, the reforms did bear fruit and led to the defense and reaffirmation of Roman Catholicism. By addressing Protestant-inspired arguments and concerns, the council laid down a path that would lead to today's Catholic Church. Doctrines, liturgies and sacraments were reaffirmed and standardized. A revised edition of the Catholic Bible was issued and a church-wide catechism was approved to instruct the church's often undereducated clergy. Church-approved art, liturgical music and spiritual devotions were encouraged to focus the faithful, and new religious orders were allowed to form, the Jesuits being the most famous and influential.

Politics

There was a political dimension, too. A new Roman Inquisition was established in 1588 to combat Protestantism in Italy and the church made alliances with Catholic-friendly monarchies throughout Europe to mutually defend and spread the Catholic faith throughout the New World. The majority of these political mechanisms were either discarded or disavowed by church authorities by the late 20th century, but today's Congregation for the Doctrine of the Faith is a direct descendant of the last inquisition and is still formally responsible for policing Catholic standards within the church.